Reducing the Radioactive Doses of Liquid Samples Taken from Reprocessing Plant Vessels by Volume Reduction

Size reduction is attractive because it should enable a solution to be analysed by much more direct, and therefore faster and simpler, methods. For instance if the traditional 7 milliliter vials used in reprocessing plants can be replaced by a vessels containing less than one microlitre, it should be possible to analyse the non-diluted solutions in gloveboxes. These vessels would be electro-mechanical, so the term MEMS might be appropriate. This paper determines a conservative estimate for the dose reduction that would be obtained if microlitre samples were extracted from an input accountancy tank at a reprocessing plant, in which the spent fuel is dissolved in nitric acid. This estimate has to take into account the self-shielding e¤ect, that varies for di¤erent low-energy and high-energy gamma-emitting isotopes. The typical composition of the solution from an input accountancy tank in a reprocessing plant is first derived by means of a burnup code. Eight di¤erent spent fuel cases are considered to cover the range of fission products, that can emit low and high energy gamma's. The neutron and gamma fluxes emitted from the classical 7 millilitre vial and from a vessel with less than a microlitre solution are calculated by means of Monte Carlo simulations. The resulting doses are calculated and compared in average and in distribution for di¤erent cases of spent fuel composition. For a volume size reduction of 6300 an averaged conservative dose reduction of 6000 is obtained.

JANSSENS-MAENHOUT Greet;  BUYST Jimmy;  PEERANI Paolo; 

2007-03-26

ELSEVIER SCIENCE SA

JRC35031

https://publications.jrc.ec.europa.eu/repository/handle/JRC35031,   

10.1016/j.nucengdes.2006.09.026,